Method and system for a bioartificial organ

ABSTRACT

Methods and systems are provided for a stem cell organ device including an array of alternating stem cell channels and fluid channels. In one example, a method may include loading a stem cell channel with stem cells and flowing blood through a fluid channel in order to allow an exchange of molecules between the stem cells and the blood.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation of U.S. Non-Provisional patentapplication Ser. No. 15/152,385 entitled “METHOD AND SYSTEM FOR ABIOARTIFICAL ORGAN” filed on May 11, 2016. U.S. Non-Provisional patentapplication Ser. No. 15/152,385 claims priority to U.S. ProvisionalPatent Application No. 62/160,440, entitled “METHOD AND SYSTEM FOR ABIOARTIFICIAL ORGAN,” filed on May 12, 2015. The entire contents of eachof the above-identified applications are hereby incorporated byreference for all purposes.

FIELD

The present description relates generally to methods and systems for abioartificial organ for supporting a patient.

BACKGROUND/SUMMARY

Patients suffering from organ disease and/or failure rely on medicaldevices to perform the necessary organ functions for treatment of theirorgan disease and/or while awaiting organ transplant. Such medicaldevices may include membranes for transferring nutrients, chemicals, orthe like, to a patient's bloodstream. In one example, bioreactor devicesmay be used to support patient's while awaiting organ transplant.Bioreactor devices may include hollow fiber membranes seeded with cells(e.g., cells of the required organ type) for performing organ functionsand transferring toxins away from and/or nutrients to the patient'sbloodstream. However, the inventors herein have recognized problems withsuch approaches. As one example, hollow fiber membranes may have issueswith cell viability and longevity. As such, cells may die over time,thereby requiring the patient to be switched to a new device. Thus,these devices may not be effective as longer term support devices forpatients. As another example, such devices may also have increasedpackaging space, thereby making the device larger and less portable.

As one example, the issues described above may be at least partiallyaddressed by a stem cell organ device, comprising a first channeladapted to house a plurality of cells, a second channel, a membranearranged between the first channel and the second channel, and a firstinlet manifold coupled to the first channel. In one example, one or moreinterior surfaces of the first inlet manifold may include guides. Assuch, when cells are injected into the first channel, the cells mayspread more evenly over and across the first channel, thereby increasinga transfer of molecules between the cells and blood flowing through thesecond channel during patient use.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a stem cell organ device and associated flow andsampling circuit.

FIG. 2 illustrates an example structure of a plurality of microchannelsused in a stem cell organ device.

FIG. 3 illustrates an embodiment of a side view of a stem cell organdevice.

FIG. 4 illustrates a top-down view of a stem cell organ device includingalternating stem cell channels and fluid channels comprising respectivemanifolds for receiving and releasing a flow of stem cells and blood.

FIGS. 5A, 5B, and 5C illustrate a stem cell organ device with a stemcell manifold and a fluid manifold, an example of a single stem cellchannel fluidly coupled to a portion of the stem cell manifold, andexample flows of stem cells without guides and with guides within a stemcell channel.

FIGS. 6A, 6B, 6C, 6D, 6E, and 6F illustrate example guides for themanifolds of the stem cell organ device.

FIG. 7 shows perspective view of an assembled stem cell organ devicewith a variable pump.

FIG. 8 shows a perspective view of a stem cell loading layer of anembodiment of a stem cell organ device.

FIG. 9 shows a perspective view of a stem cell channel layer of anembodiment of a stem cell organ device.

FIG. 10 shows a perspective view of a membrane layer of an embodiment ofa stem cell organ device.

FIG. 11 shows a perspective view of a fluid channel layer of anembodiment of a stem cell organ device.

FIG. 12 shoes a perspective view of a fluid loading layer of anembodiment of a stem cell organ device.

FIGS. 13A-13C show a relationship between loading channels and channelsof the channel layer of an embodiment of a stem cell organ device.

FIG. 14 illustrates a flow chart of a method for preparing and operatinga stem cell organ device.

FIG. 15 shows a method for operating the stem cell organ device with thevariable pump and multi-fluid manifold.

FIG. 16 shows a stem cell layer of another embodiment of a stem cellorgan device.

FIG. 17 shows a fluid layer of another embodiment of a stem cell organdevice.

FIG. 18 shows a top perspective view of an assembled stem cell organdevice.

FIG. 19 shows a side perspective view of the assembled stem cell organdevice of FIG. 18.

FIG. 20 shows a side view of the assembled stem cell organ device ofFIGS. 18-19.

FIG. 21 shows a first graph of a first protein secreted by stem cells ofa first stem cell organ test device over a period of 14 days.

FIG. 22 shows a second graph of a second protein secreted by stem cellsof the first stem cell organ test device over a period of 14 days.

FIG. 23 shows a third graph of a first protein secreted by stem cells ofa second stem cell organ test device over a period of 25 days.

DETAILED DESCRIPTION

The following description relates to systems and methods for operating astem cell organ device including an array of alternating stem cellchannels and fluid channels. The stem cell organ device may be, locatedin a healthcare facility (hospital, clinic, ICU, etc.) and/or a portabledevice that allows a patient to use the device outside of a medicaloffice (e.g., at work, at home, at a store, etc.). More specifically,the stem cell organ device may include at least one stem cell layerincluding a plurality of stem cell channels, at least one fluid layerincluding a plurality of fluid channels, and at least one membraneseparating the stem cell layer and the fluid layer. During a first, stemcell loading period and media mode, stem cells (as well as mediaincluding nutrients) may be loaded into the plurality of stem cellchannels and additional media including various nutrients may slowlyflow through the plurality of fluid channels of the stem cell organdevice. Once the device is ready for patient treatment (e.g., the loadedcells have affixed to the membrane and have grown to a threshold level),the fluid channels are flushed with a flushing solution to remove themedia (such as saline). Blood from a patient may then be directedthrough the fluid channels during a treatment period. The stem cells andblood may be monitored via a HPLC or other cell assay device in order todetermine a viability and/or performance of the cells, as shown inFIG. 1. FIGS. 2-6 show various embodiments of the stem cell organdevice. In one embodiment, the stem cell channels and fluid channelseach comprise ridges in order to allow a single layer of cells to flowthrough the respective channels, as shown in FIG. 2. A stem cell organdevice with a first manifold and a second manifold is shown in FIG. 3. Atop-down view of the stem cell organ device along with a view removingthe stem cell channel such that the fluid channel is illustrated isshown in FIG. 4. A first pump coupled to a first manifold and a secondpump coupled to a second manifold are shown along with a plurality ofalternating stem cell and fluid channels in FIG. 5A. A single stem cellchannel with an inlet manifold comprising guides is shown in FIG. 5B.Example flows with and without guides are shown in FIG. 5C. Variousembodiments of guides of the stem cell organ device are shown in FIGS.6A, 6B, 6C, 6D, 6E, and 6F. A top of the stem cell device including thefluid portion (or layer) is shown in FIG. 7. Layers of a firstembodiment of a stem cell organ device, namely a stem cell loadinglayer, a stem cell channel layer, a membrane layer, a fluid channellayer, and a fluid loading layer are shown in FIGS. 8, 9, 10, 11, and 12respectively. A relationship between loading channels and stem-cellchannels is shown in FIGS. 13A-13C. A method for loading the stem cellchannels with stem cells and operating the stem cell organ device withor without flowing blood is shown in FIG. 14. FIG. 15 shows a method foroperating a blood pump of the stem cell organ device. A secondembodiment of the stem cell organ device is shown in FIGS. 16-17. Thesecond embodiment of the stem cell organ device includes at least onestem cell layer including stem cell channels connected between inlet andoutlet stem cell manifolds (as shown in FIG. 16) and at least one fluidlayer including fluid channels connected between inlet and outlet fluidmanifolds (as shown in FIG. 17). The at least one stem cell layer and atleast one fluid layer may be separated from one another via a membranelayer, such as the membrane layer shown in FIG. 10. FIGS. 18-20 showdifferent views of an embodiment of an assembled stem cell organ device.In one example, the stem cell organ device of FIGS. 18-20 may include asingle stem cell layer and a single fluid layer separated by a singlemembrane. In other embodiment, the stem cell organ device may includemultiple stem cell, fluid, and membrane layers within the assembled stemcell organ device. FIGS. 21-23 show testing results from several stemcell organ test devices that were loaded with a plurality of stem cells.Over a period of 14-25 days, the stem cells were allowed to grow andaffix to the membrane of the stem cell organ devices. The graphs ofFIGS. 21-23 show protein secretion levels of the stem cells over thetesting periods, thereby showing evidence of cell growth and viability.Thus, stem cells grown within the stem cell organ device may be used ina treatment mode to transfer nutrients and toxins to/from a patient'sblood running through the fluid layer(s) of the stem cell organ device.

Turning now to FIG. 1, a system 100 comprising a stem cell organ device102, a cell assay system (e.g., such as a high performance liquidchromatography (HPLC) system) 140, and a computer 150 is illustrated. Inone example, the stem cell organ device 102 is a micro energy andchemical system (MECS) based stem cell organ device. The MECS based stemcell organ device is a microfluidic device including an array ofparallel microchannels and may be referred to herein as a microchanneldevice. As depicted in FIG. 1, the stem cell organ device 102 comprisesone stem cell channel 104 (represented by slanted lines) and one fluidchannel 106 (represented by crisscross lines) separated by a membrane108 (represented by a dotted box). However, in some embodiments, aplurality of stem cell channels, fluid channels, and membranes (e.g.,filters) may exist, as shown in FIGS. 2-3, and thus the stem cell organdevice 102 includes an array of alternating channels.

The stem cell channel 104 is adapted to hold various types of stem cells(e.g., stem cells for liver, pancreas, kidney, lung, etc.) to functionas an external organ. The stem cells may be grown outside of the stemcell channel 104 and injected into the stem cell channel 104 via aninjector 123. The fluid channel 106 is adapted to flow various fluidstherein. For example, the fluid channel 106 may flow cell nutrients(also referred to herein as media) during a media mode (which mayinclude a period of loading and/or growing cells), saline during aflushing mode (such as when transitioning between the media mode and atreatment or blood mode), and blood during a patient treatment mode(which includes transferring nutrients to the patient's bloodstream andtoxin away from the patient's bloodstream via the stem cells). Amembrane 108 is arranged between the fluid channel 106 and the stem cellchannel 104. The membrane 108 prevents the flow of fluid between thefluid channel 106 and the stem cell channel 104. However, the membrane108 does allow diffusion of smaller molecules (or ions) between theblood and stem cell channels, such as allowing the transfer of toxinsfrom blood flowing through the fluid channel 106 to the cells loadedinto the stem cell channel 104. The membrane 108 may also allowdiffusion of molecules, such as ions, salts, nutrients, etc., from thecells in the stem cell channel 104 to the blood flowing through thefluid channel 106. The membrane 108 may prevent the diffusion ofproteins from the fluid channel 106 to the stem cell channel 104. In oneexample, the membrane 108 may allow salt, water, and toxins (e.g., urea)to flow from the fluid channel 106 to the stem cell channel 104. As oneexample, the membrane 108 is a relatively flat sheet membrane includinga variety of pores capable of exchanging certain-sized molecules or ions(e.g., molecules smaller than the pore size) between the blood or mediaflowing in the fluid channel 106 and the cells in the stem cell channel104 without allowing diffusion of the stem cells into the fluid channel106 or blood or media into the stem cell channel 104. The membrane 108chemistries and porosities may be different based on a type of stem cellpresent in the stem cell channel 104 (e.g., kidney stem cells, liverstem cells, pancreas stem cells, etc.). Further, the membrane 108 may bea microporous membrane having pores with a diameter on the micro-scale.In this way, the membrane 108 is adapted for microfiltration betweenelements in the fluid channel 106 and elements in the stem cell channel104. By including stem cells to perform filtering functions of adesignated organ with a patient's bloodstream, the stem cell organdevice 102 simulates functions of a corresponding organ (e.g.,bioartificial organ).

The stem cells in the stem cell channel 104 may become saturated withtoxins and/or degrade in function after a threshold duration of use(e.g., a threshold duration of flowing blood through the device, such as12 hours, in one example). The threshold time may be adjusted based on apatient, the flow rate of blood through the device, and the compositionof the blood flowing through the device. For example, a greater flowrate of blood through the fluid channel 106 may result in a decreasedthreshold duration of use (e.g., 8 hours). In order to ensure properfiltration of blood, the stem cells may be sampled via the HPLC 140 (oralternate cell assay system) via instructions from the computer 150 toopen a stem cell pressure controller 110 and flow a metered amount ofstem cells (e.g., 10-100 μL) into stem cell sample tubes 114. The stemcell pressure controller 110 is electrically coupled to and may receiveinstruction from the computer 150. Likewise, a corresponding sample ofblood flowing through the fluid channel 106 may be sampled and injectedinto the HPLC 140 via instructions from the computer 150 to open a bloodpressure controller 112 and flow a metered amount of blood (e.g., 10-100μL) to blood sample tubes 116. A stem cell sample tube 114 may besampled by the HPLC 140 and a corresponding blood sample tube 116 may besubsequently sampled by the HPLC 140. The HPLC 140 may provideinformation to the computer 150 regarding a concentration of compoundsin the stem cell and the blood. For example, if a stem cell sample ismeasured to have a relatively low concentration of a first molecule bythe HPLC 140, while a blood sample is measured to have a concentrationof the first molecule (e.g., such as a toxin or molecule that issupposed to be transferred from the blood to the stem cells) is greaterthan a threshold (e.g., an amount of the first molecule that may bepotentially harmful to a patient), then diffusion between the stem cellchannel 104 and the fluid channel 106 may be below a desired diffusionrate. As another example, if a stem cell sample has a toxin levelgreater than a threshold stem cell toxin level (e.g., an amount oftoxins in the stem cells where the desired diffusion rate may no longerbe met), then the stem cells may need to be replaced due to degradation(e.g., decreased viability). As another example, if the stem cell samplehas a threshold level of certain molecule, or a ratio of certainmolecules within the sample is outside of a threshold range, decreasedcell viability may be indicated. A portion of the stem cell organ device102 may be at least partially transparent (e.g., clear) such that a usermay visualize a state of the stem cells (e.g., such as the viability ofthe stem cells) in the stem cell channel 104 and visually determine ifthe stem cells are still viable (e.g., functional).

If the computer (e.g., electronic controller) 150 in communication withvarious sensors of the stem cell organ device (such as cell viabilitysensors, which may include the HPLC described above) determines thatcell viability of the stem cells within the stem cell channel 104 isbelow a threshold level, the stem cell organ device 102 use may beterminated so that the stem cell organ device 102 may be recharged(e.g., reloaded) with new stem cells or new cell media to foster anutrient rich environment for the stem cells to continue to beviable/functional or the stem cell organ device may be replaced with anew device containing viable stem cells. As such, the stem cell organdevice 102 may include an additional blood, nutrient or flush solutionpump or pumps for flowing cell media through the stem cell channel 104.In another example, the stem cell channel 104 may be coated with amaterial that contains the cell media and/or nutrients to increased stemcell viability.

If it is determined that the stems cells within the stem cell channel104 need to be replaced, the degraded stem cells may first be removed,or flushed, from the stem cell channel 104. In order to replace degradedstem cells, the computer 150 signals a stem cell actuator 132 to actuatea plunger 126 of a syringe 124 to inject an amount of stem cells (e.g.,new and viable stem cells) into the stem cell channel 104. The amount ofstem cells may be based on an intended duration of operation of the stemcell organ device 102 or a difference between the toxin level in thestem cells and the threshold stem cell toxin level. For example, as thedifference increases, the amount of stem cells injected also increases.The amount of stem cells injected may be controlled by one or more of astem cell inlet pressure controller 128 and the stem cell actuator 132.The stem cell inlet pressure controller 128 is at least partially openwhen stem cells are injected into the stem cell channel 104 by thesyringe 124.

The stem cells in the stem cell channel 104 are not continuouslyreplaced. As one example, the stem cells remain in the stem cell channel104 until a toxin level (e.g., a level of a molecule that indicatesdecreased cell viability) in the stem cell channel 104 exceeds thethreshold stem cell toxin level. Therefore, the stem cell channel isonly opened to the injector 123 and an inlet manifold of the stem cellchannel (e.g., stem cell inlet manifold) during filling (or refilling)of the stem cell channel 104 with stem cells.

In an alternate embodiment, the stem cells may not be replaced withinthe stem cell organ device and instead the degraded device may bereplaced with a different stem cell organ device containing viable stemcells.

In one embodiment, the fluid channel 106 may always be open during stemcell organ device 102 operation such that saline, cell media, or bloodis always flowing through the fluid channel 106 via a pump 117 (e.g.,such as a syringe pump, centripetal pump, or roller pump). For example,during a treatment period when blood flows through the device,unfiltered blood from a patient may flow in a first end of the fluidchannel 106 via the pump 117, be filtered as it passes through the fluidchannel 106, exits out of a second end of the fluid channel 106, andthen returns to a patient's bloodstream within the patient. In oneexample, the computer 150 signals an actuator 130 to actuate a plunger120 of the syringe 118 of the pump 117 to inject a volume of blood intothe fluid channel 106. The volume of blood injected into the fluidchannel 106 may be based on a rate of blood flowing out of the fluidchannel 106 and into a patient (not shown). The volume of blood injectedmay be controlled by one or more of a blood inlet pressure controller122 and the blood actuator 130 based on signals received from thecomputer 150. The plunger 120, syringe 118, and blood actuator 130 mayform the pump 117, in one example.

In another embodiment, a multi-fluid variable pump may be used to injectsaline, media, and blood into the stem cell organ device duringoperation (e.g., in a flushing phase, media phase, or treatment/bloodphase of device operation). The multi-fluid variable pump may beelectrically coupled to a controller with instructions for carrying outthe operation. The controller may be an electronic controller containingnon-transitory memory configured to store the instructions for carryingout operation of the multi-variable pump. For example, the controllermay actuate various actuators of the variable pump in order to flowmedia (e.g., containing various cell nutrients), saline, or bloodcontinuously through the fluid channel(s) of the stem cell organ deviceuntil a treatment period (e.g., filtering blood) is complete or the stemcells are no longer viable. As described above, cell viability may bedetermined via HPLC 140. As an example, additionally or alternatively,stem cell viability may be determined by an optical sensor. The opticalsensor (e.g., a spectrophotometer) may measure a color, absorbance,and/or UV emittance. If the color changes (cells become darker), lightabsorbance changes (decreases), and/or UV emittance changes (decreases),then the cells may no longer be viable and operation of the stem cellorgan device may be terminated. In one example, termination of the stemcell organ device includes one or more of disabling blood flow, removingthe degraded stem cells, and washing the stem cells channels with salineor stem cell media (e.g., Luria broth, growth media, etc.). In anotherexample, termination of the stem cell organ device includes one or moreof disabling blood flow through the fluid channels, flushing the fluidchannels with saline, and/or replacing the stem cell organ device with anew device containing stem cell channels with viable stem cells.

FIG. 1 depicts a system 100 for filtering blood in a fluid channel viastem cells in a stem cell channel via a membrane, where the membrane isdisposed between the fluid channel and the stem cell channel. An examplestructure of the stem cell organ device 102, including a stem cellchannel and a blood flow channel, will be described in greater detailbelow with respect to FIG. 2.

Turning now to FIG. 2, a system 200 depicts an array of microchannels,such as the fluid channel 106 and stem cell channel 104 shown in FIG. 1,of varying size. For example, a stem cell channel width may vary basedon a type of stem cell loaded into the stem cell channel (e.g., 10-100microns). In this way, the stem cell channel may comprise a single layerof stem cells. A top support plate 201 is in face-sharing contact with atop plate 202. A membrane 204 (e.g., similar to membrane 108 of FIG. 1)is located between the top plate 202 and a two sided plate 206. The twosided plate 206 and the top plate 202 comprise ridges 203. Stem cellsmay flow into and be loaded onto a space (e.g., channel) formed betweenthe top plate 202 and the membrane 204 while blood may flow in a space(e.g., channel) formed between the membrane 204 and the two sided plate206. The ridges 203 may be used to guide a stem cell or blood flow in astem cell channel or a fluid channel, respectively. As depicted, theridges 203 vary in size from a first ridge to a subsequent ridge. Insome embodiments, additionally or alternatively, a size of the ridges ofthe top plate 202 may not be equal to a size of the corresponding ridgesof the two sided plate 206 nearest the membrane 204. In another example,the ridges of the top plate 101 and a surface of the two-sided plate 206facing the membrane 204 may be substantially equal. In this way, the topplate 202 and a first side of the membrane 204 may be in contact withstem cells while the portion of the two sided plate 206, nearest themembrane 204, and a second side of the membrane 204 may be in contactwith blood.

A portion of the two sided plate 206 nearest a membrane 208 may be incontact with stem cells (e.g., the portion of the two sided plate 206nearest the membrane 208 and the membrane 208 create a stem cellchannel). The portion of the two sided plate 206 nearest the membrane208 comprises ridges substantially equal to the ridges of the top plate202. In this way, ridges in contact with stem cells may be substantiallyequal in shape and size. A portion of a two sided plate 210 nearest themembrane 208 (e.g., the portion of the two sided plate 210 nearest themembrane 208 and the membrane 208 create a fluid channel) may be incontact with blood, or another fluid flowing through the fluid channel.The ridges of the portion of the two sided plate nearest the membrane208 may be substantially equal to the ridges of the portion of the twosided plate 206 nearest the membrane 204. In this way, ridges in contactwith blood (or saline or media) may be substantially equal in shape andsize.

A distance 205 between the top plate 202 and the portion of the twosided plate 206 nearest the membrane 204 may be less than a distance 207between the portion of the two sided plate 206 nearest the membrane 208and the portion of the two sided plate 210 nearest the membrane 208. Inthis way, a width of the stem cell channel and the fluid channel may bealtered along the system 200. Thus, the array of microchannels may havediffering widths.

Stem cells may lie between the membrane 212 and a surface of the twosided plate 210 facing the membrane 212. Blood may lie between themembrane 212 and a bottom plate 214. The bottom plate 214 is inface-sharing contact with a bottom support plate 216. The bottom plate214 and the portion of the two sided plate 210 nearest the membrane 212comprise ridges substantially similar to ridges in a fluid channel and astem cell channel, respectively.

In some embodiments, the distance 205 may be substantially equal for allmicrochannels in a stem cell organ device include an array (e.g.,plurality) of microchannels. Additionally or alternatively, the ridgesof the microchannels may all be equal in size and shape (e.g., a firstridge of a stem cell channel may be substantially equal to a secondridge of the stem cell channel).

FIG. 2 depicts an example structure of a plurality of stem cell channelsand fluid channels of an example stem cell organ device with ridges tohelp guide flow within the channel. FIG. 3 illustrates another exampleof a stem cell organ device including a plurality of microchannels ofsimilar type to the channels shown in FIGS. 1 and 2.

Turning now to FIG. 3, a side-on view of a stem cell organ device 300comprising a plurality of microchannels 302 (e.g., an array ofmicrochannels, also referred to as a microchannel array or system) isdepicted. The microchannels 302 are depicted as being evenly spacedapart and comprising ridges substantially equal to adjacent ridges of asame channel. For example, ridges in a first stem cell channel 312 aresubstantially equal to ridges in a second stem cell channel 314 in bothsize and shape. Furthermore, ridges in a first fluid channel 316 aresubstantially equal to ridges in a second fluid channel 318 in both sizeand shape. Ridges in stem cell channels may not be equal to ridges influid channels. Alternatively, ridges in the stem cell channels may besubstantially equal to ridges in fluid channels in both size and shape.The stem cell organ device 300 may be an example of the stem cell organdevice 102 of FIG. 1 and thus may function similarly as described above.

The stem cell organ device 300 further comprises a stem cell manifold304 with a stem cell supply port 306. Likewise, on an opposite side ofthe stem cell organ device 300, there lies a fluid manifold 308 with afluid injection port 310. Dashed arrows indicate a fluid flow direction(e.g., of blood, saline, or media) through the stem cell organ device300.

The stem cell manifold 304 is fluidly coupled to only the stem cellchannels of the stem cell organ device 300. Likewise, the fluid manifold308 is fluidly coupled to only the fluid channels of the stem cell organdevice 300. The stem cell supply port 306 may house a first pumpingmechanism (e.g., syringe 124). The fluid supply port 310 may house asecond pump mechanism (e.g., pump mechanism 118).

Turning now to FIG. 4, a top-down view of a stem cell channel 402 and afluid channel 452 of a stem cell organ device 400 are depicted. The stemcell organ device 400 may be the same as the stem cell organ device 300of FIG. 3 and/or the stem cell organ device 102 of FIG. 1. Slanted linesdepict an area where stem cells may be present within the stem cellorgan device 400. Crisscross lines depict an area where fluid (such asblood) may be present within the stem cell organ device. The first view401 of FIG. 4 shows a top view of the device where the stem cell channel402 is positioned on top of a fluid channel and thus only the stem cellchannel 402 is shown. The second view 450 of FIG. 4 shows a top view ofthe device where the stem cell channel 402 has been removed so the fluidchannel 452 is uncovered and may viewed.

The stem cell channel 402 is fluidly coupled to a stem cell manifold 404via a stem cell manifold pathway 406. A stem cell injection, or flow ofstem cells, may occur at the stem cell manifold 404 and stem cells mayflow through the stem cell manifold pathway 406 to the stem cell channel402 and other stem cell channels (e.g., the additional stem cellslocated below the stem cell channel 402). For example, when loading thestem cell organ device 400 with stem cells, stem cells are injected viaa port in the stem cell manifold 404 and stem cells may then flowthrough the stem cell manifold pathway 406 and through the stem cellchannel 402 and the other stem cell channels in order to load each ofthe stem cell channels of the stem cell organ device 400 with stemcells, prior to patient use. The stem cell manifold 404 and/or the stemcell manifold pathway 406 may comprise guides to assist in evenlydistributing the stem cells to a plurality of stem cell channels of thestem cell organ device 400. The guides will be discussed in greaterdetail below.

During device loading, stem cells may flow out of stem cell channel 402via a stem cell outlet manifold pathway 408 leading to a stem celloutlet manifold 410. The stem cell outlet manifold 410 is on an oppositeside of the stem cell organ device 400 compared to the stem cell inletmanifold 402. The stem cell channel 402 may further comprise a sieve forcapturing stem cells during stem cell loading while allowing a bulkfluid to pass through the sieve and exit the stem cell channel 402. Morespecifically, an end of the stem cell channel 402 coupled to the stemcell outlet manifold pathway 408 may include the sieve positioned acrossan exit from the stem cell channel 402 to the stem cell outlet manifoldpathway 408. In one example, the sieve may include a solid barrierincluding a plurality of apertures, where a diameter of each of theapertures is smaller than a diameter of the cells. The bulk fluid may bea mixture of fluid and nutrients used to grow the stem cells (referredto herein as cell media). The sieve may be removed during removal ofdegraded stem cells and then re-introduced during stem cell loading.

The fluid channel 452 is fluidly coupled to a fluid inlet manifold 454via a fluid inlet manifold pathway 456. The fluid inlet manifold 454 andthe fluid inlet manifold pathway 456 are fluidly coupled to only thefluid channel 452 and other fluid channels of the stem cell organ device400. Fluid (such as blood, saline, or media) leaving the fluid channel452 exits through a fluid outlet manifold pathway 458 to a fluid outletmanifold 460. Arrow 462 depicts a fluid (e.g., blood) flow directionthrough the fluid channel 452, fluid inlet manifold 454 and fluid outletmanifold 460.

The fluid inlet manifold 454 lies directly below the stem cell outletmanifold 410. Likewise, the fluid outlet manifold 460 lies directlybelow the stem cell inlet manifold 404. For a stem cell organ devicewith a plurality of alternating stem cell channels and fluid channels,the stem cell inlet manifold and fluid outlet manifold may alsoalternate corresponding to the alternating pattern of the stem cellchannels and the fluid channels. Likewise the stem cell outlet manifoldand the fluid inlet manifold may also alternate corresponding to thealternating pattern of the stem cell channels and the fluid channels.The stem cell inlet manifold, stem cell outlet manifold, fluid inletmanifold, and fluid outlet manifold will be discussed in greater detailbelow.

FIG. 4 depicts a top-down view of a stem cell organ device with a stemcell channel and a fluid channel comprising respective manifolds forreceiving and releasing (or flowing) stem cells or fluid (e.g., blood,saline, or media), respectively. FIG. 5A depicts a side-on view of astem cell organ device with alternating stem cell and fluid manifolds.

Turning now to FIG. 5A, a stem cell organ device 500 is shown, the stemcell organ device 500 comprising a plurality of stem cell inletmanifolds 502 and a plurality of fluid outlet manifolds 514 on a firstside of the stem cell organ device and a plurality of fluid inletmanifolds 504 and a plurality of stem cell outlet manifolds 516 on asecond side of the stem cell organ device 500, opposite the first side.The stem cell organ device 500 further comprises a plurality of stemcell channels 510 and a plurality of fluid channels 512, the pluralityof stem cell channels 510 and plurality of fluid channels 512alternating with one another such that each stem cell channel 510 isseparated from other stem cell channels 510 by a fluid channel 512. Thestem cell organ device 500 may be used as and operate similarly to thestem cell organ device 102 of FIG. 1.

Larger dashed arrows in the stem cell channels 510 represent a directionof stem cell flow when the stem cell organ device 500 is being loadedwith stem cells before patient use. Smaller dashed arrows in the fluidchannels 512 represent a direction of fluid flow when the stem cellorgan device 500 is in use. The larger dashed arrows are greater in sizethan the smaller dashed arrows.

As one example, each of the stem cell inlet manifolds 502 is fluidlycoupled to one another through a stem cell inlet connecting channelconnected to each stem cell inlet manifold 502. All of the stem cellinlet manifold 502 and the stem cell inlet connecting channel may formone stem cell inlet manifold unit. As such, when stem cells are injectedvia a stem cell injector (as explained further below) into a first stemcell inlet manifold 502 (e.g., the top or outer stem cell inlet manifold502), stem cells may flow between all of the fluidly connected stem cellinlet manifolds 502 and through all of the stem cell channels 510. In analternate embodiment, each of the stem cell inlet manifolds 502 may becoupled to its own stem cell injector and stem cells may be injectedindividually into each stem cell inlet manifold 502 and thecorresponding stem cell channel 510. Similarly, each of the stem celloutlet manifolds 516, each of the fluid inlet manifolds 504, and each ofthe fluid outlet manifolds 514 and corresponding connecting channels mayform a stem cell outlet manifold unit, a fluid inlet manifold unit, anda fluid outlet manifold unit, respectively.

Each stem cell inlet manifold 502 is fluidly coupled to only stem cellchannel 510 and not fluid channels 512. Further, each stem cell inletmanifold 502 is physically coupled to only one stem cell channel 510.The stem cell channels 510 are also fluidly coupled to the stem celloutlet manifolds 516. Each fluid inlet manifold 504 is fluidly coupledto only fluid channels 512. Further, each fluid inlet manifold 504 isphysically coupled to only one fluid channel 512. The fluid channels 512are also fluidly coupled to the fluid outlet manifolds 514. As depicted,the stem cell channels 510 and the fluid channels 512 alternate. Thus,the stem cell inlet manifolds 502 and the fluid outlet manifolds 514alternate on the first side of the stem cell organ device 500 in orderto align with the stem cell channels 510 and the fluid channels 512.Likewise, the fluid inlet manifolds 504 and the stem cell outletmanifolds 516 alternate on the second side of the stem cell organ device500 in order to align with the fluid channels 512 and the stem cellchannels 510. In this way, fluid may only flow from the fluid inletmanifolds 504, through the fluid channels 512, and into the fluid outletmanifolds 514, without mixing with stem cells. Likewise, the stem cellsmay only flow from the stem cell inlet manifolds 502, through the stemcell channels 510, and into the stem cell outlet manifolds 516, withoutcrossing over to the fluid channels 512 (e.g., due to a membraneseparating the fluid channels and stem cell channels, such as themembranes shown in FIGS. 1-3).

In an alternate embodiment, the stem cell inlet manifolds may bearranged on a same side of the stem cell organ device as the fluid inletmanifolds and the stem cell outlet manifolds may be arranged on a sameside of the stem cell organ device as the fluid outlet manifolds. Inthis way, a loading direction of stem cells into the stem cell channelsmay be the same as a flow direction of fluid (e.g., blood, saline, ormedia) through the fluid channels.

A cross-section of each manifold of the stem cell inlet manifolds 502,fluid inlet manifolds 504, fluid outlet manifolds 514, and stem cellinlet manifolds 516 yields a triangular structure. Therefore, themanifolds 502, 504, 514, and 516 are shaped as triangular prisms.However, in alternate embodiments, alternate shapes are possible.

As described above, during a treatment mode when the stem cell organdevice is connected to a patient, blood from the patient is continuouslydelivered to the fluid inlet manifolds 504, the fluid channels 512, andthe fluid outlet manifolds 514 in order to transfer molecules and/orions to/from the blood, and perform other blood filtering operations,before the filtered (e.g., treated) blood is returned to the patient. Arate of blood entering the fluid channels 512 may be equal to a rate ofblood exiting the fluid channels 512. In this way, a volume of blood inthe fluid channel 512 is kept relatively constant. In one example, apump upstream or downstream of the stem cell organ device 500 maycontinuously pump blood from the patient and through the stem cell organdevice 500.

As described above, stem cells are not continuously fed to the stem cellchannels 510. Stem cells are loaded into the stem cell channels 510prior to device use in the treatment mode and then the stem cells remainin the stem cell channels 510 until the stem cells become degraded(e.g., until viability of the stem cells reduces below a thresholdlevel). The degradation (or level of viability) may be measured by acell assay, such as a cell assay performed by HPLC system, measuring alevel of certain molecules indicating low cell viability in the stemcells being greater than a threshold. In another example, cell viabilitymay be determined by a user visualizing the stem cell degradation (e.g.,degradation may cause discoloration, size change, shape change,cloudiness, etc.). Upon determination of degradation, the stem cellchannels 510 may be opened to the stem cell inlet manifold 502 and tothe stem cell outlet manifold 516. The degraded stem cells may beflushed out of the stem cell channels 510 and then new stem cells may beflown into the stem cell channels 510 to reload the device. During astem cell loading procedure, a flow of stem cells into the stem cellchannels 510 may be equal to a flow of stem cells out of the stem cellchannel 510. The stem cells may flow through the stem cell channels 510in a single layer.

A stem cell injector 506 is fluidly coupled to the stem cell inletmanifold 502, as described above with respect to FIG. 1. A flow of stemcells from the stem cell injector 506 is perpendicular to a flow of stemcells in the stem cell channels 510. Likewise, in one example, a flow ofblood from a blood injector 508 (or blood pump coupled to the manifold)is perpendicular to a flow of blood in the fluid channels 512.

Turning now to FIG. 5B, a top-down representation 530 of an individualstem cell channel 510 is depicted. The stem cell channel 510 comprises astem cell inlet manifold 502 and a stem cell injector 506, as describedabove. The stem cell inlet manifold 502 comprises guides 532. The guides532 may be located on one or more inner surfaces of the stem cell inletmanifold 502. For example, the guides 532 may be on one or more of abottom, inner surface, a top, inner surface, and side, inner surfaces ofthe stem cell inlet manifold 502. The guides 532 help guide the stemcells to flow uniformly into and through the stem cell channel 510 suchthat a coating of the stem cell channel 510 is even. Arrow 534represents a direction of flow for the stem cells after injection andinto the stem cell channel 510.

FIG. 5C depicts a first example flow 542 of stem cells through the stemcell channels without guides in the stem cell inlet manifold and asecond example flow 544 of stem cells through the stem cell channelswith guides in the stem cell inlet manifold. The first example flow 542resembles a laminar flow of stem cells through the stem cell channelthat has a parabolic shape. For example, laminar flow in a pipe (e.g.,channel) results in a parabolic flow profile where the velocity of flowvaries from zero at the walls of the channel to a maximum along thecross-sectional center of the channel. As depicted, a flow front 546 iscurved due to the flow being laminar and unguided. The laminar flowprofile may result in uneven distribution of stem cells in the stem cellchannel. Uneven distribution of stem cells may lead to decreasedmolecular exchange between the blood and stem cells during device use(e.g., a rate of exchange is less than a threshold rate). Furthermore,the laminar flow profile has an uneven pressure across its flow front.For example, a pressure along the cross-sectional center of the channelis greater than a pressure along the walls of the channel. In this way,stem cells flowing along the cross-sectional center of the channel maybe damaged upon reaching an end of the channel due to the greaterpressure.

The second example flow 544 resembles a plug flow of stem cells throughthe stem cell channel, or uniform flow distribution across across-section of the stem cell channel. As depicted, a flow front 548 ofthe plug flow is relatively linear across the channel. The plug flowprofile may evenly distribute stem cells to and along the stem cellchannel due to the flow being guided by the guides in the inlet manifoldcoupled to the stem cell channel. The guides may aid in decreasing thesurface tension of the stem cell inlet manifold, thereby more evenlydistributing the flow of stem cells across the cross-section of the stemcell channel. Furthermore, a pressure of the flow of stem cells is evenfrom the wall of the stem cell channel to a cross-sectional center ofthe stem cell channel. In this way, the stem cell channel may be morequickly and evenly loaded with guides compared to the loading withoutguides described above.

FIGS. 5A, 5B, and 5C illustrate alternating stem cell manifold and fluidmanifolds fluidly coupled to alternating stem cell channels and fluidchannels, respectively. The stem cell inlet manifolds may compriseguides to help evenly distribute stem cells in their correspondingchannels. FIGS. 6A, 6B, 6C, 6D, 6E, and 6F depict various inner surfacesof the stem cell inlet manifold. As described above, the inlet manifoldsresemble triangular prisms. Therefore, a top, bottom, or side innersurface of the inlet manifolds yields a triangle, as depicted in FIGS.6A-6F.

Turning now to FIG. 6A, an embodiment 600 comprising an inner surface ofa stem cell inlet manifold 602 comprising a stem cell injection port 604is depicted. Thus, the embodiment 600 may show a top inner surface of astem cell inlet manifold 602. However, a bottom or side inner surface ofthe inlet manifold 602 may include similar guides as shown for the topsurface. As described above, the stem cell inlet manifold 602 flows stemcells to stem cell channels of a stem cell organ device.

The embodiment 600 further depicts the inner surface of the stem cellinlet manifold 602 with a plurality of guides 606. The guides areinterspersed along the inner surface of the stem cell inlet manifold 602such that there are regions of the inner surface of the stem cell inletmanifold 602 comprising guides 606 and remaining regions that do notcomprise guides 606. In this way, the regions that do not compriseguides 606 separate the regions comprising guides 606 from one another.As depicted in the embodiment 602, the guides may be asymmetric and/orunorganized. The guides 616 may be laser etchings, protrusions, grooves,ingots, stamps, and/or other suitable alterations to the inner surfaceof the stem cell inlet manifold 602 such that the loading of stem cellsinto the stem cell channel is more uniform. The guides 606 may crossover one another such that they are perpendicular. Additionally oralternatively, the guides may include one or more sections of parallellines, crisscrossing lines, overlapping lines, circles, swirls, andoverlapping curved lines distributed either evenly or unevenly over asurface of the one or more interior surfaces.

Turning now to FIG. 6B, an embodiment 610 comprising an inner surface ofa stem cell inlet manifold 612 comprising a stem cell injection port 614is depicted. Thus, the embodiment 610 may show a top inner surface of astem cell inlet manifold 612. However, a bottom or side inner surface ofthe inlet manifold 612 may include similar guides as shown for the topsurface. As described above, the stem cell inlet manifold 612 flows stemcells to stem cell channels of a stem cell organ device.

The embodiment 610 further depicts the inner surface of the stem cellinlet manifold 612 with a plurality of guides 616. The guides areinterspersed along the inner surface of the stem cell inlet manifold 612such that there are regions of the inner surface of the stem cell inletmanifold 612 comprising guides 616 and remaining regions that do notcomprise guides 616. In this way, the regions that do not compriseguides 616 separate the regions comprising guides 606 from one another.As depicted in the embodiment 612, the guides may be symmetric and/ororganized. The guides 616 may be laser etchings, protrusions, grooves,ingots, stamps, and other suitable alterations to the inner surface ofthe stem cell inlet manifold 612 such that the loading of stem cellsinto the stem cell channel is uniform. As depicted, the guides 616 maycross over one another such that they are perpendicular.

Turning now to FIG. 6C, an embodiment 620 comprising an inner surface ofa stem cell inlet manifold 622 comprising a stem cell injection port 624is depicted. Thus, the embodiment 620 may show a top inner surface of astem cell inlet manifold 622. However, a bottom or side inner surface ofthe inlet manifold 622 may include similar guides as shown for the topsurface. As described above, the stem cell inlet manifold 622 flows stemcells to stem cell channels of a stem cell organ device.

The embodiment 620 further depicts the inner surface of the stem cellinlet manifold 622 with a plurality of guides 626. The guides areinterspersed along the inner surface of the stem cell inlet manifold 622such that there are regions of the inner surface of the stem cell inletmanifold 622 comprising guides 626 and remaining regions that do notcomprise guides 626. In this way, the regions that do not compriseguides 626 separate the regions comprising guides 626 from one another.The guides 626 may be laser etchings, protrusions, grooves, ingots,stamps, and other suitable alterations to the inner surface of the stemcell inlet manifold 622 such that the loading of stem cells into thestem cell channel is uniform. As depicted, the guides 626 may be linearand of a varying thickness. The guides 626 may be angled and overlappingone another. The guides 626 may be angled toward or parallel with a stemcell flow direction of stem cells being loaded into stem cell channels.Additionally or alternatively, the guides 626 may vary in size andlength.

Turning now to FIG. 6D, an embodiment 630 comprising an inner surface ofa stem cell inlet manifold 632 comprising a stem cell injection port 634is depicted. Thus, the embodiment 630 may show a top inner surface of astem cell inlet manifold 632. However, a bottom or side inner surface ofthe inlet manifold 632 may include similar guides as shown for the topsurface. As described above, the stem cell inlet manifold 632 flows stemcells to stem cell channels of a stem cell organ device.

The embodiment 630 further depicts the inner surface of the stem cellinlet manifold 632 with a plurality of guides 636. The guides areinterspersed along the inner surface of the stem cell inlet manifold 632such that there are regions of the inner surface of the stem cell inletmanifold 632 comprising guides 636 and remaining regions that do notcomprise guides 636. In this way, the regions that do not compriseguides 636 separate the regions comprising guides 636 from one another.The guides 636 may be laser etchings, protrusions, grooves, ingots,stamps, and other suitable alterations to the inner surface of the stemcell inlet manifold 632 such that the loading of stem cells into thestem cell channel is uniform. As depicted, the guides 636 may becircular or elliptical. The guides 636 may vary in thickness. The guides636 may be angled to and overlapping one another. Additionally oralternatively, the guides 636 may vary in size and length.

Turning now to FIG. 6E, an embodiment 640 comprising an inner surface ofa stem cell inlet manifold 642 comprising a stem cell injection port 644is depicted. Thus, the embodiment 640 may show a top inner surface of astem cell inlet manifold 642. However, a bottom or side inner surface ofthe inlet manifold 642 may include similar guides as shown for the topsurface. As described above, the stem cell inlet manifold 642 flows stemcells to stem cell channels of a stem cell organ device.

The embodiment 640 further depicts the inner surface of the stem cellinlet manifold 642 with a plurality of guides 646. The guides areinterspersed along the inner surface of the stem cell inlet manifold 642such that there are regions of the inner surface of the stem cell inletmanifold 642 comprising guides 646 and remaining regions that do notcomprise guides 646. In this way, the regions that do not compriseguides 646 separate the regions comprising guides 646 from one another.The guides 646 may be laser etchings, protrusions, grooves, ingots,stamps, and other suitable alterations to the inner surface of the stemcell inlet manifold 642 such that the loading of stem cells into thestem cell channel is uniform. As depicted, the guides 646 may be wavy orstraie. The guides 646 may vary in thickness. The guides 646 may beangled to and overlapping one another. Additionally or alternatively,the guides 646 may vary in size and length.

Turning now to FIG. 6F, an embodiment 650 comprising an inner surface ofa stem cell inlet manifold 652 comprising a stem cell injection port 654is depicted. Thus, the embodiment 650 may show a top inner surface of astem cell inlet manifold 652. However, a bottom or side inner surface ofthe inlet manifold 652 may include similar guides as shown for the topsurface. As described above, the stem cell inlet manifold 652 flows stemcells to stem cell channels of a stem cell organ device.

The embodiment 650 further depicts the inner surface of the stem cellinlet manifold 652 with a plurality of guides 656. The guides areinterspersed along the inner surface of the stem cell inlet manifold 652such that there are regions of the inner surface of the stem cell inletmanifold 652 comprising guides 656 and remaining regions that do notcomprise guides 656. In this way, the regions that do not compriseguides 656 separate the regions comprising guides 656 from one another.The guides 656 may be laser etchings, protrusions, grooves, ingots,stamps, and other suitable alterations to the inner surface of the stemcell inlet manifold 652 such that the loading of stem cells into thestem cell channel is uniform. As depicted, the guides 656 may be mixtureof guides 616 of FIG. 6B, guides 626 of FIG. 6C, guides 636 of FIG. 6D,and guides 646 of FIG. 6E. Although now depicted, the guides 656 mayoverlap with other guides of a dissimilar shape. For example, circularregions of the guides 656 may overlap with wavy regions of the guides656. The guides 646 may vary in thickness. The guides 656 may be angledto and overlapping one another. Additionally or alternatively, theguides 656 may vary in size and length.

In some embodiments, additionally or alternatively, a first guide (e.g.,circular guides) may be located on the bottom inner surface of the stemcell inlet manifold while a different guide (e.g., linear guides) may belocated on the top inner surface of the stem cell inlet based on a typeof stem cell loaded into the stem cell channel. For example, a stem cellinlet manifold for kidney stem cells may be substantially equal to orunequal to a stem cell inlet manifold for liver stem cells.

FIGS. 6A-6F depict various guides located along a stem cell inletmanifold to be used for uniformly loading stem cells in a stem cellchannel. FIG. 7 depicts an embodiment of an assembled stem cell organdevice.

Specifically, FIG. 7 shows a perspective view of a stem cell organdevice 700. In the current view, only the fluid inlet and outletmanifolds are visible. The stem cell organ device 700 may be usedsimilarly to any of the stem cell devices described herein. The stemcell organ device 700 may be compatible with one or more of a kidney,liver, pancreas, lung, etc. stem cells in one example. In anotherexample, the stem cell channels stem cell organ device 700 may becompatible with only one of the kidney, liver, pancreas, lung, etc. stemcells based on a stem cell channel size. As described above, the stemcell channels are configured to allow stem cells to flow in a singlefile in order to increase transfer between the stem cells and apatient's blood. The stem cell organ device 700 does not use dialysate.

An axis system 790 comprises three axes, an x-axis parallel to thehorizontal direction, a y-axis parallel to the vertical direction, and az-axis perpendicular to both the x and y axes. A central axis 795 of thestem cell organ device is shown by a dashed line.

The stem cell organ device 700 comprises a glass cover layer 702, aloading layer 710, and a channel layer 720. The glass cover 702 isvertically higher than the loading layer 710 which is vertically higherthan the channel layer 720. The above three layers depict a fluidportion of the stem cell organ device 700. Thus, in the currentembodiment, the fluid portion is vertically higher than a stem cellportion and a membrane separating the stem cell and blood portions. Acase (not shown) may be used to house the above components duringoperation.

The glass cover 702 is transparent and in face-sharing contact to theloading layer 710. Liquid and gas may flow between the glass cover 702and the loading layer 710. An optical sensor or a patient may lookthrough the glass cover 702 to visibly determine a state of the stemcells (e.g., viable or degraded). The glass cover 702 may be thickerthan the loading layer 710 and the channel layer 720. The glass cover702 may hermetically seal along an outer edge with the loading layer 710such that fluid may not flow to an ambient atmosphere.

The loading layer 710 comprises an inlet header 712 with a series ofbifurcating channels 716 fluidly coupled to an inlet 714 at a singlepassage. An inlet 704 extends downward from an outer surface of theglass layer 702 to the inlet 714. The bifurcating channels 716 lead tothe fluid channels 722 of the channel layer 720.

The stem cell layer positioned below the fluid layer may include similarbifurcating channels that may comprise any of the above describedetchings with respect to FIGS. 6A, 6B, 6C, 6D, 6E, and 6F. This allowsthe bifurcating channels to decrease laminar flow and evenly load thestem cell channels. Uneven flow may lead to bubbles or uneven filling ofthe stem cell channels, thereby reducing blood filtering during a stemcell device operation.

A number of fluid channels 722 (and similarly, stem cell channels) maybe equal to a number of bifurcating channels 716. The fluid channels 722align with the bifurcating channels 716 along the x and y axes. Adirection of fluid flow to the fluid channels 722 and/or stem cell flowto the stem cell channels is described below with reference to FIGS.13A-13C.

An outlet 706 is located on an opposite side of the stem cell organdevice 700 compared to the inlet 704. The outlet 706 and inlet 704 arealigned along the central axis 795. However, in alternate embodiments,the outlet 706 and inlet 704 may be offset from one another relative tothe central axis 795. The outlet 706 is larger than the inlet 704 in oneexample. The fluid channels 722 are fluidly coupled to the outlet 706 byan outlet passage 718. The fluid channels 722 may converge proximal tothe outlet passage 718 such a single outflow of fluid may flow from thechannel layer 720 to the outlet passage 718.

A pump 730 is electrically coupled to a controller 780, wherein thecontroller 780 comprises computer-readable instructions for actuatingvarious actuators of the pump 730 based on one or more of a type or sizeof stem cell device, stem cell type, blood conditions, etc. Theconditions are further described below with respect to FIG. 15. In someembodiments, the pump and the controller may be combined into a singledevice such that the pump houses the controller in order to reduce aprofile of the stem cell organ device 700. The pump 730 is coupled to amanifold 740 comprising four ports, namely a flush port 742, a mediaport 744, a blood port 746, and a bypass port 748. The pump 730 includesactuators corresponding to each of the above ports in order to flowfluid through only a single port at a time. In some embodiments,additionally or alternatively, the pump 730 may flow fluid through twoor more ports simultaneously. As an example, blood may flow through thebypass port 748 while media flow through the media port 744. The flushport 742 and the media port 744 are fluidly coupled to the inlet 704.The flush port may provide saline while the media port 744 may providemedia (e.g., including one or more cell nutrients). The blood port 746is also fluidly coupled to the inlet 704. The bypass port 748 is fluidlycoupled to a bypass passage, which directs patient blood away from thefluid manifold. In one example, the bypass passage may redirect bloodback to a patient. In this way, manifold 740 may be referred to hereinas a multi-fluid manifold that connects various fluid ports flowingvarious fluids (e.g., saline, media, and blood) to a fluid manifold andfluid channels of the stem cell organ device. Control of the pump 730may adjust which type of fluid, through a corresponding port of themanifold 740, flows into and through the fluid channels of the stem cellorgan device.

FIGS. 8-13C show an embodiment of a stem cell organ device whichincludes separated loading layers (including inlet manifolds) andchannel layers (including stem cell or fluid channels). The separatedlayers may stack on top of one another. The stem cell organ devicedescribed in FIGS. 8-13C may function similarly to the other stem cellorgan devices described herein with reference to FIGS. 1-7.

FIG. 8 shows a stem cell loading layer 800. Stem cells may be loadedinto the stem cell loading layer 800, as described above. The stem cellloading layer 800 comprises an inlet manifold 802 opposite an outletmanifold 804. The inlet manifold 802 comprises an inlet 810, which is asingle pathway leading to loading channels 820. The loading channels 820bifurcate into a plurality of channels. In one example, a volume of theloading channels 820 may decrease by a factor of two following eachbifurcation. Decreasing the volume in this way allows a channel upstreamof a bifurcation to be substantially equal in volume to the two channelsdownstream of the bifurcation. In another example, the width of theloading channels 820 may remain substantially constant followingbifurcation.

The outlet manifold 804 comprises an outlet 830 for discharging stemcells, or excess media loaded with the stem cells, from the stem cellloading layer 800. The outlet 830 aligns with a central axis 895 of thestem cell loading layer 800. The stem cell loading layer 800 issymmetric about the central axis 895. In the current embodiment, theoutlet 830 is rectangular. In other embodiments, the outlet 830 may besquare, circular, triangular, diamond, elliptical, etc. In alternateembodiments, the inlet 810 and outlet 830 may not be aligned with thecentral axis 895 and may instead be offset from and arranged on oppositesides of the central axis 895.

The outlet manifold 804 is located on an opposite side of the stem cellloading layer 800 compared to the inlet manifold 802. The manifolds arecompletely separated by a length of the stem cell channels 820. In thisway, stem cells may not flow directly from the inlet manifold 802 to theoutlet manifold 804.

FIG. 9 shows a stem cell channel layer 900 comprising a plurality ofstem cell channels 902, inlets 904, and sieves 906. The stem cellchannel layer 900 is located directly below and in face-sharing contactwith the stem cell loading layer 800 of FIG. 8. The stem cell channels902 align with the stem cell loading channels 820 of FIG. 8.Specifically, ends of the stem cell loading channels 820 align with theinlets 904. The inlets 904 guide stem cells one at a time through thestem cell channels 902. Sieves 906 are located at an end of the stemcell channels 902 opposite the inlets 904. The sieves may prevent stemcells from flowing out of the stem cell channels 902, while allowingions, fluids, etc. to flow through its openings. Media flowing throughthe sieves 906 may flow into the outlet manifold 804 of FIG. 8. The stemcell channels 902 are linear as shown, but may be other suitable shapesin other embodiments.

FIG. 10 shows a membrane 1000 composed of a selective barrier(semi-permeable membrane) capable of allowing the transfer of selectsmall molecules, ions, etc. The membrane 1000 is directly below the stemcell channel layer 900. In one example, the membrane 1000 may allowwater, salts (Na, K, Ca, etc.), sodium bicarbonate, urea, and othersmall molecules to pass between stem cell channels and fluid channels.Furthermore, the membrane 1000 may prevent passage of red blood cells,large proteins, and other large molecules. In this way, the membrane1000 may comprise pores (not shown) with a diameter correspondingsmaller molecules. In another example, the membrane 1000 may comprisecharged pores and allow passage of similarly charged molecules.Additionally or alternatively, the membrane 1000 may allow passage ofmolecules based on polarity, wherein a molecule with a higher polaritymay pass through the membrane 1000 faster than a molecule with a lowerpolarity. The aforementioned molecules flow down a concentrationgradient through the membrane 1000. In one example, water and salt mayflow from blood, through the membrane 1000, and into the stem cellchannels 902 of FIG. 9 as long as a concentration of the above compoundsin the stem cell channels is lower than a concentration in the fluidchannels.

FIG. 11 shows a fluid channel layer 1100 comprising a plurality of fluidchannels 1102. The fluid channels 1102 may minimize an area ofturbulence and stagnation, as well as blood-air interfaces in order todecrease a likelihood of blood clotting. An inlet 1104 and an outlet1106 are located on opposite sides of the fluid channels 1102. In oneexample, the inlet 1104 may be on an opposite side of a stem cell organdevice compared to the inlets 904 of FIG. 9 of the stem cell channels902. In this way, a pump may load stem cells and blood 180° out of phasewith respect to a direction of flow. In an alternate embodiment, theinlet 1104 may be on a same side of the stem cell organ device as theinlets 904 of FIG. 9 of the stem cell channels 902.

The fluid channels 1102 do not comprise sieves. Blood may flow out theoutlet 1106 back to a patient. As discussed above, when not treating thepatient's blood, an alternate fluid such as saline or media, may flowthrough the fluid channels 1102. The fluid channel layer 1100 is locateddirectly below the membrane 1000. In this way, the fluid channel layer1100 may communicate with the stem cell channel layer 900 through themembrane 1000. In this way, the fluid channel layer 1100 and the stemcell layer 900 are physically separated while being fluidly coupledthrough the membrane 1100. The fluid channels 1102 may align with thestem cell channels 902. This allows blood to flow directly below andin-line with the stem cells loaded into the stem cell channels 902. Inone example, a number of fluid channels 1102 may be exactly equal to anumber of stem cell channels 902. The fluid channels 1102 are linear asshown, but may be other suitable shapes in other embodiments.

FIG. 12 shows a fluid loading (e.g., feed) layer 1200 with an inletmanifold 1202 and an outlet manifold 1204. The inlet manifold 1202comprises an inlet 1206 fluidly coupled to fluid loading channels 1208.The fluid loading channels 1208 originate as a single channel fluidlycoupled to the inlet 1206 before bifurcating to a plurality of fluidloading channels 1208 equal to the number of fluid channels 1102 of FIG.11. The inlet 1206 does not align with a central axis 1295 of the fluidloading layer 1200. An outlet 1210 is aligned with the inlet 1206 andthus, also misaligned with the central axis 1295. In alternateembodiments, the inlet 1206 and outlet 1210 may be offset from thecentral axis 1295 by varying amounts and the inlet 1206 and outlet 1210may be positioned on opposite sides of the central axis 1295.

An outlet passage 1212 leads to the outlet 1210. The fluid loading layer1200 is located directly below the fluid channel layer 1100 of FIG. 11.In this way, fluid from the fluid loading channels 1208 flow ups intothe fluid channels 1102, where the fluid flows along an entire length ofthe fluid channels 1102 before flowing down into the outlet passage 1212and out the outlet 1210.

The fluid inlet manifold 1202 is physically and fluidly separated fromthe fluid outlet manifold 1204. The manifolds are located on oppositesides of the fluid loading layer 1200. The fluid inlet manifold 1202 islocated below the stem cell outlet manifold (e.g., stem cell outletmanifold 804 of FIG. 8) along a common vertical axis. The fluid outletmanifold 1202 is located below the stem cell inlet manifold (e.g., stemcell inlet manifold 802 of FIG. 8).

FIGS. 7-12 depict various embodiments of the above described stem cellorgan device. In one example, the stem cell organ device may comprisetwo laser cut polymer layers to transport stem cells to the stem cellchannels. A top glass plate may be used for support and visualization ofthe stem cell channels. Additionally or alternatively, a bottom glassplate may also be used such that light may shine through an entirety ofthe stem cell organ device. The stem cell organ device may furthercomprise an inlet header, where the inlet header is a binary fractalstructure to aid in guiding the stem cells to evenly load the stem cellchannels. The stem cell channel exits may comprise a sieve to trap thestem cells while allowing media, saline, or other bulk fluids to passthrough the stem cell channel. Stem cells and/or bulk fluid may beintroduced to the stem cell channels via the inlet header. The inletheader may operate in a manner similar to the inlet manifold describedabove.

FIG. 13A shows a cross-section 1300A of loading channels 1302Ainterfaced with channels 1304A. The channels may be stem cell channelsor fluid channels (which may flow media, blood, or saline). As shown,the loading channels 1302A are oblique to the channels 1304A prior toinsertion points 1306A. The channels overlap at the insertion point, aswill be described in greater detail with respect to FIG. 13C.

FIG. 13B shows a cross-section 1300B of channel 1304B interfaced withoutlets 1308B. As shown, the channel 1304B is a single, larger passagecompared to the channels 1304A of FIG. 13A. In one example, the channels1304A may merge to form the channel 1304B. The channel interfaces withthe outlets 1308B, which lead to an outlet chamber 1310B.

FIG. 13C shows a cross-section 1300C of a stem cell loading channel1302C fluidly coupled to a stem cell channel 1304C. An axes system 1395Ccomprises two axes, a vertical axis and a horizontal axis. The loadingchannel 1302 may be used similarly to one of the loading channels 820 ofFIG. 8. The stem cell channel 1304 may be used similarly to one of thestem cell channels 902. The loading channel 1302C and the channel 1304Care both parallel to the horizontal axis. Stem cells flow from theloading channel 1302C along the horizontal axis, down into the stem cellchannel 1304C along the vertical axis at an insertion point 1306C, andback along the horizontal axis through the stem cell channel 1304C. Inthis way, a direction of stem cell flow turns 90° twice in order to loadthe stem cell channels. A flow direction of stem cells in the channelsis parallel. By turning prior to entering the channel 1304C, air bubblesmay be removed due to the sudden directional change in stem cell flow,which may provide more even stem cell loading into the channel 1304C.

FIG. 14 depicts a method for loading stem cells into the stem cellchannels and operating a stem cell organ device, such as any of the stemcell organ devices described herein with reference to FIGS. 1-13A-13Cand 16-20.

Turning now to FIG. 14, a method 1400 for loading stem cells into aplurality of stem cell channels of a stem cell organ device andoperating the stem cell organ device is illustrated. The method 1400further describes determining stem cell degradation within the device.

The method 1400 begins at 1402 which includes injecting stem cells andmedia into the stem cell channels. Each stem channel may include asieve, as described above, in order to contain the stem cells in thestem cell channel while allowing the media, containing nutrients andused to grow the stem cells, to flow through the sieve and out of thestem cell channel. The method at 1402 may further include, at the sametime as injecting the stem cells and media into the stem cell channels,flowing (e.g., at a flow rate below a threshold) additional mediacontaining various cell nutrients through the fluid channels of the stemcell organ device. In some examples, before loading the stem cells intothe stem cell channels at 1402, both the stem cell channels and fluidchannels may be primed with a fluid (such as saline and/or various cellnutrients) for a duration (e.g., 1-2 days). For example, the stem cellorgan device may be primed (and loaded) with the fluid simultaneouslyfrom both sides (from both the stem cell channel side and the fluidchannel side) in order to reduce the likelihood of rupture of themembrane separating the stem cell channels and fluid channels.

At 1404, the method 1400 includes determining if a stem cell channel isfully loaded. The stem cell channel may be fully loaded when the stemcells fill an entirety of the stem cell channel. This may be indicatedvia the clear and/or transparent window pane coupled to or above thestem cell channels, as described above and below, such that a patientmay visually determine if the stem cell channels are fully loaded.Alternatively, the stem cell organ device may comprise an indicatorcapable of indicating an amount of stem cells in the stem cell channel.

If the stem cell channels are not full, then the method 1400 proceeds to1406 to continue loading stem cells into the stem cell channels untilthe stem cell channels are fully loaded. If the stem cell channels arefully loaded, then the method 1400 continues to 1408 to disable the stemcell flow to the stem cell channels. This may include capping an inletor inlet to port to all of the stem cell channels and/or disabling astem cell pump (or injector) coupled to the inlet port of the stem cellchannels.

At 1409, the method 1400 includes continuing to flow cell media to andthrough the fluid channels prior to a patient blood flow through thefluid channels. In this way, the stem cells may continue to receivenutrients from the media (through the membrane) in order to increasestem cell viability and keep the stem cells alive.

At 1410, the method 1400 includes flushing the fluid channels withsaline (or an alternate flushing solution) in order to remove the mediaused to grow the stem cells from the fluid channels.

At 1412, the method 1400 includes, after connecting the stem cell organdevice to a patient, continuously flowing the blood of the patient intothe fluid channels of the stem cell organ device. During operation ofthe stem cell organ device, the blood is continuously cycled through thefluid channels while the stem cells remain in the stem cell channels. Byflowing blood into the fluid channels, the blood and the stem cellsbegin to transfer ions, salts, and toxins down their respectiveconcentration gradients (e.g., flow from high concentration to lowconcentration). For example, toxins flow from the blood to the stemcells while nutrients such as sodium and potassium may flow from thestem cells to the blood.

At 1414, the method 1400 includes monitoring and/or assaying the stemcells in order to determine a viability of the stem cells within thestem cell channels. As described above, the stem cells may be monitoredvia visualization or they may be assayed via a HPLC or other suitablecell assay devices. In one example, the viability of the stem cells maybe continuously monitored throughout the duration of device use.

At 1416, the method 1400 includes determining if the stem cells areviable (or if stem cell viability is over a threshold). If the stemcells are not viable (e.g., viability of the stem cells decreases belowthe threshold which may be based on a cell viability model), the methodproceeds to 1418 to discontinue blood flow through the fluid channels.The stem cell organ device may then be disconnected from the patient andflow circuit and replaced with a new, unloaded (e.g., empty devicewithout stem cells) or viable stem cell organ device (containing alreadygrown and viable stem cells).

Alternatively, if the stem cells are viable, the method continues to1420. At 1420, the method 1400 includes determining if blood flowtreatment (e.g., therapy) is complete. Blood flow treatment may becomplete via measuring a biomarker indicating a blood purity greaterthan a threshold purity. For example, a blood sample may indicate ablood toxin concentration being less than a threshold toxinconcentration, thereby increasing the blood purity to a blood puritygreater than the threshold purity.

If the blood flow treatment is not complete, then the method 1400proceeds to 1422 to continue flowing blood through the fluid channels ofthe stem cell organ device. The blood flow may continue to be monitoreduntil treatment of the blood flow is complete. If the blood flowtreatment is complete, then the method 1400 proceeds to 1424 to stopflowing blood, flush the fluid channels with saline, and then to beginflowing media through the fluid channels. By flowing saline into thefluid channels, the blood is removed from the fluid channels. By flowingmedia to the fluid channels, the stem cell viability may be maintaineduntil a subsequent treatment session is requested. In this way, the stemcells may be maintained within a viable state and used in future patienttreatments.

FIG. 15 includes a method 1500 for a portable stem cell organ device isshown. This allows the patient to conduct routine daily activities(e.g., walk, drive, work, etc.) without worrying about dialysis at adoctor's office. The stem cell device comprises a programmable pumpcapable of pumping a variety of fluids into and out of the stem celldevice to maintain a desired operation of the stem cell device withlittle to no input from the patient. The method 1500 may be conductedbefore, during, or after method 1400 of FIG. 14.

Method 1500 begins at 1502, initiating operation of a multi-fluidmanifold (e.g., fluid manifold 740 of FIG. 7) of the stem cell device.The multi-fluid manifold may be coupled to or part of a fluid inletmanifold (e.g., fluid inlet manifold 1202 of FIG. 12 or fluid inletmanifold 1702 of FIG. 17) of the stem cell organ device. In one example,initiating operation may include turning on a variable pump (e.g., pump730 of FIG. 7) fluidly coupled to the multi-fluid manifold. As explainedabove, the multi-fluid manifold may be fluidly coupled to a plurality offluid channels of the stem cell organ device. The multi-fluid manifoldmay comprise a plurality of ports, wherein each of the ports maycorrespond to a different function. In one example, the multi-fluidmanifold may comprise four different ports corresponding to fourdifferent stem cell device modes. A first port may correspond to abypass mode, a second port may correspond to a blood mode, a third portmay correspond to a media mode, and a fourth port may correspond to aflush mode. In some examples, additionally or alternatively, themulti-fluid manifold may comprise a fifth port corresponding to acleaning mode. In other examples, cleaning may be conducted via thefourth port and thus may utilize the same fluid used in the flush mode.The pump may be electronically controlled by a controller electricallyactuating actuators of the pump based on a desired mode of operation.Thus, the pump may comprise actuators corresponding to each of the portsof the multi-fluid manifold.

At 1504, the method 1500 determines if stem cells are loaded into thestem cell organ device. If the stem cells are not loaded, then themethod 1500 proceeds to 1506 and enters the media mode and bypass mode.For example, the method at 1504 may include switching operation of thepump and multi-fluid manifold to the media mode and bypass mode, whichare explained in more detail below with reference to the method at 1508.

At 1508, the method 1500 includes flowing media through the fluidchannels while bypassing blood around (and not through) the fluidchannels of the stem cell organ device. This may include the pumpdirecting media through the third port to the fluid channels (e.g.,fluid channels 802 of FIG. 8 or fluid channels 1704 of FIG. 17). Thepump also directs blood through a bypass passage by flowing bloodthrough the first port and flowing blood back to a patient withoutflowing blood to the stem cell organ device and through the fluidchannels. This prevents blood from being filtered and may be used duringconditions when blood mode conditions are not met. During the method at1504, stem cells may be loaded into the stem cell channels of the stemcell organ device following method 1400 presented at FIG. 14 (e.g.,according to the methods at 1402-1408).

In some embodiments, additionally or alternatively, the method 1500 mayassay the stem cells prior to loading the stem cells in order todetermine if the stem cells are viable. The assaying may be conducted byan optical sensor which may determine a color, absorbance, density(number of stem cells) of the stem cells as will be described below.

Returning to 1504, if the method 1500 determines that the stem cells areloaded, then the method 1500 proceeds to 1510 to determine if the fluidchannels have been flushed with a desired fluid (such as saline or someother flushing solution) following flowing media through the fluidchannels. If the fluid channels have not been flushed yet to remove themedia, then the method 1500 proceeds to 1512 to enter the flush mode andthe bypass mode, as described further below with reference to 1514.

At 1514, the method 1500 includes initiating the flush mode by flowing aflush solution (e.g., saline) to and through the fluid channels of thedevice. This may include the pump directing the flush solution throughthe fourth port of the multi-fluid manifold to the fluid channels. As anexample, the pump may direct a volume of flush solution equal to thevolume of the fluid channels. As another example, the pump may direct avolume of flush solution greater than the volume of the fluid channels.The method at 1514 also includes directing (via the pump) blood throughthe bypass passage by flowing blood through the first port and flowingblood back to the patient without flowing blood to the stem cell organdevice and through the fluid channels.

Returning to 1510, if the method 1500 determines the fluid channels havebeen flushed with the flush solution, then the method 1500 proceeds to1516 to enter the blood mode. The blood mode includes the pump directingblood through the second port, where the blood flows to the fluidchannels. Blood is returned to the patient after flowing through thestem cell organ device. In this way, two blood passages to the patientexist, the bypass passage and a blood mode passage. The blood modeincludes flowing the blood at a desired rate. Blood flow below thedesired rate may increase a likelihood of blood coagulating and bloodflow above the desired rate may decrease diffusion of molecules from theblood to the stem cells.

At 1518, the method 1518 includes filtering blood with the stem cellsvia the membrane separating the fluid channels flowing the blood andstem cell channels containing the stem cells. This may include the pumpcontinuously flowing blood through the fluid channels of the stem celldevice via the second port of the multi-fluid manifold. As describedabove, during blood filtering, the stem cells are stagnant in the stemcell channels. Thus, the pump does not direct stem cells through thethird port during blood mode operation. Molecules pass through themembrane between the stem cells and the blood. As described above, salt,water, toxins, and other molecules may pass from the blood to the stemcells, while nutrients and other molecules may pass from the stem cellsto the blood.

At 1520, the method 1500 includes determining if the stem cells areviable. The stem cells may be viable based on characterizationsdetermined by the optical sensor described above. In one example,additionally or alternatively, the patient may visibly determine if thestem cells are viable by looking through a glass cover of the stem cellorgan device and determining if a color change has occurred. In anotherexample, the stem cell organ device may indicate stem cell degradationbased on the optical sensor reading. The indication may include a visualand/or audible indication. For example, a light may be activated and/ora beeping sound may occur. Additionally or alternatively, the stem cellorgan device may vibrate in response to the stem cells no longer beingviable (e.g., degraded).

If the stem cells are degraded, then the method 1500 proceeds to 1522 todisable the blood mode and return the blood to the patient. The methodat 1522 may also include stopping patient treatment and disconnectingthe stem cell organ device so that it may be replaced with anotherdevice containing viable cells.

Returning to 1520, if the method 1500 determines stem cells are stillviable, then the method 1500 proceeds to 1526 to determine if blood iffully filtered. An optical sensor, which may be the same optical sensorused to characterize the stem cells, may measure salt concentration,water concentration, toxin concentration, and other suitable propertiesfor determining if the blood is fully filtered. In one example, thesalt, water, and toxin concentrations may all be less than acorresponding threshold concentration. If the blood is not fullyfiltered, then the method 1500 proceeds to 1527 to continue operating inthe blood mode until the blood is fully filtered.

If the blood is fully filtered, then the method 1500 proceeds to 1528 toexit the blood mode and returns blood back to the patient. Exiting theblood mode includes no longer flowing blood to the stem cell organdevice. The method 1500 may no longer flow blood to the multi-fluidmanifold.

At 1530, the method 1500 includes determining if the stem cells arestill viable, as described above. In one example, the stem cell devicemay continuously measure stem cell viability. If the stem cells are nolonger viable, the method 1500 proceeds to 1532 to disconnect the stemcell organ device from the treatment system so that it may be replacedwith another device containing viable cells.

If the stem cells are still viable, then the method 1500 proceeds to1534 to enter the media mode, as described above with reference to themethods at 1506 and 1508. For example, the pump may flow media throughthe fluid channels to provide nutrients to the stem cells and keep themalive until a following treatment event.

FIGS. 16-17 show a stem cell layer 1600 and fluid layer 1700 of anotherembodiment of a stem cell organ device which may operate similarly tothe other stem cell organ devices described above. The stem cell layer1600 shown in FIG. 16 and the fluid layer 1700 shown in FIG. 17 areseparated from one another via a membrane (e.g., such as membrane 1000shown in FIG. 10).

At least one stem cell layer 1600, at least one membrane, and at leastone fluid layer 1700 may be combined together to form a stem cell organdevice unit, such as the stem cell organ device unit shown in FIGS.18-20. In one embodiment, the stem cell organ device unit may includemultiple stem cell layers, membranes, and fluid layers arranged in analternating fashion, as described above. In another embodiment, the stemcell organ device unit may only include a single stem cell layer, asingle membrane, and a single fluid layer.

FIG. 16 shows the stem cell layer 1600 including a stem cell inletmanifold 1602, a plurality of stem cell channels 1604, and a stem celloutlet manifold 1606 all arranged in the same plane (e.g., plane of thelayer). The stem cell inlet manifold 1602 includes an inlet 1608 and aplurality of branched loading channels 1610. The loading channels 1610branch from the inlet 1608 to inlets of each individual stem cellchannel 1604. The stem cell outlet manifold 1606 includes an outlet (oroutlet passage) 1614 coupled to a plurality of sieves 1616 which arecoupled to the plurality of stem cell channels 1604.

As shown in FIG. 16, the inlet 1608 and outlet 1614 are each offset froma central axis 1612 of the stem cell layer (which may be a commoncentral axis for the stem cell layer, fluid layer, membrane, and entirestem cell organ device unit). Specifically, the inlet 1608 is arrangedon an opposite side of the stem cell layer 1600 from the outlet 1614,relative to (and across from) the central axis 1612. This offset natureof the inlets and outlets of the stem cell layer 1600 and fluid layer1700 (as discussed further below) may reduce pressure within the deviceand reduce sagging of the membrane and restriction of flow within thedevice (e.g., in the fluid channels). In alternate embodiments, theinlets and outlets of the stem cell layer and fluid layer may be offsetfrom the central axis 1612 by a larger or smaller amount (e.g., distancefrom the central axis) than shown in FIGS. 16 and 17.

FIG. 17 shows the fluid layer 1700 including a fluid inlet manifold1702, a plurality of fluid channels 1704, and a fluid outlet manifold1706 all arranged in the same plane. The fluid inlet manifold 1702includes an inlet 1708 and a plurality of branched loading channels1710. The loading channels 1710 branch from the inlet 1708 to inlets ofeach individual fluid channel 1704. The inlet 1708 may be coupled to amulti-fluid manifold (e.g., such as multi-fluid manifold 740 shown inFIG. 7). The fluid outlet manifold 1706 includes an outlet (or outletpassage) 1714 coupled to a plurality of outlets 1716 of the plurality offluid channels 1704.

As shown in FIG. 17 and introduced above, the inlet 1708 and outlet 1714are each offset from the central axis 1612 of the fluid layer (which maybe a common central axis for the stem cell layer, fluid layer, membrane,and entire stem cell organ device unit). Specifically, the inlet 1708 isarranged on an opposite side of the fluid layer 1700 from the outlet1714, relative to (and across from) the central axis 1612. As shown inFIGS. 16 and 17, the inlet 1608 and inlet 1708 are aligned with oneanother on a same, first side of the device relative to the central axis1612 and the outlet 1614 and outlet 1714 are aligned with one another ona same, second side of the device relative to the central axis 1612.Thus, a direction of flow of stem cells through the stem cell channels1604 when loading the device with stem cells may the same as a directionof flow of fluid through the fluid channels 1704.

FIGS. 18-20 show an embodiment of an assembled stem cell organ deviceunit 1802 containing at least one stem cell layer (such as the stem celllayer 1600 shown in FIG. 16), at least one membrane (such as themembrane 1000 shown in FIG. 10), and at least one fluid layer (such asfluid layer 1700 shown in FIG. 17). Specifically, FIG. 18 shows a topperspective view 1800 of the stem cell organ device unit 1802 with thefluid layer visible at the top of the unit. FIG. 19 shows a sideperspective view 1900 of the stem cell organ device unit 1802 with thestem cell layer visible. FIG. 20 shows a side view 2000 of the stem cellorgan device unit 1802.

The stem cell organ device unit 1802 shown in FIGS. 18-20 includes a topplate 1803, a bottom plate 1804, and a plurality of layers 1806. Theplurality of layers 1806 may include at least one of each of the stemcell layer, the fluid layer, and the membrane. Specifically, themembrane is positioned between the stem cell layer and fluid layer andall three layers 1806 are sandwiched between the top plate 1803 and thebottom plate 1804. The top plate 1803 and bottom plate 1804 arephysically and fluidly secured to one another such that no fluid exitsthe sides of the device via a plurality of fasteners (e.g., screws andnuts) 1808 positioned through aligned apertures of the top and bottomplates and the layers 1806. The plurality of fasteners 1808 arepositioned around an outer perimeter of the stem cell organ device unit1802. The top plate 1803 and bottom plate 1804 may be made of atransparent material (e.g., glass or plastic) such that a user mayvisualize the layers within the unit. As such, a user may visualizefluid flow and/or stem cell viability of the unit.

The stem cell organ device further includes a fluid inlet port 1810which is fluidly coupled to the fluid inlet (e.g., inlet 1708 of FIG.17) of the fluid layer and is configured to couple to a fluid pumpand/or multi-port manifold of the stem cell organ device. The stem cellorgan device also includes a fluid outlet port 1812 which is fluidlycoupled to the fluid outlet (e.g., outlet 1714 of FIG. 17) of the fluidlayer. The stem cell organ device further includes a stem cell inletport 1902 (shown in FIG. 19) fluidly coupled to the stem cell inlet(e.g., inlet 1608 of FIG. 16) of the stem cell layer and a stem celloutlet port 1904 (also shown in FIG. 19) fluidly coupled to the outlet(e.g., outlet 1614 of FIG. 16) of the stem cell layer.

A complete stem cell organ device may include one or more stem cellorgan device units, such as the stem cell organ device unit shown inFIGS. 18-20. In one embodiment, the stem cell organ device may include aplurality (e.g., at least two) of stem cell organ device units coupledin series with one another such that fluid (such as blood) flows througha first stem cell organ device (from the inlet to outlet) and thenthrough at least a second stem cell organ device (from the inlet tooutlet). In another embodiment, the stem cell organ device may include aplurality (e.g., at least two) of stem cell organ device units coupledin parallel with one another such that fluid (such as blood) flowsimultaneously, in parallel, through multiple stem cell organ deviceunits. The arrangement (e.g., series or parallel) and number of stemcell organ device units of the complete stem cell organ device may beselected based on a desired clearance level (e.g., desired amount oftransfer of toxins and nutrients between the cells and blood within thedevice), duration of device use (e.g., treatment period or durationwhere a patient's blood is being filtered by the stem cells loadedwithin the device), and/or cell type.

In an experimental efficacy study, a plurality of stem cell organ deviceunits (such as the units shown in FIGS. 18-20) were loaded with aplurality of stem cells. The stem cells used in the study were from ahuman hepatoma cell line (HepG2). However, alternate cell types may havebeen used as well. After a period of first priming the device withsaline and/or media, the unit was loaded with the stem cells. The stemcells were allowed to grow and attach to the membrane as media wasflowed through the fluid channels of the fluid layer of the unit for aperiod of 14-25 days. Each day, an assay assessing the function andviability of the cells within the unit was taken. Common proteinssecreted by living HepG2 cells include the plasma protein albumin andApo lipoprotein (ApoB). FIGS. 21-23 show graphs of protein levels(measured in weight/volume) measured over a period of days followingloading the unit with the stem cells. Specifically, FIG. 21 shows afirst graph 2100 of ApoB protein secreted by stem cells of a first stemcell organ test device over a period of 14 days, FIG. 22 shows a secondgraph 2200 of albumin secreted by the stem cells of the first stem cellorgan test device over a period of 14 days, and FIG. 23 shows a thirdgraph 2300 of ApoB protein secreted by stem cells of a second stem cellorgan test device over a period of 25 days. The graphs in FIGS. 21-23show that the functionality of the HepG2 stem cells were maintainedwithin the stem cell device unit through the duration of the study asevidenced by the steady increase of secretion from Day 1 to the endpoint (Day 14 or day 25) of both ApoB and albumin.

In this way, stem cells may be grown to mimic a variety of organs (e.g.,liver, pancreas, kidney, lung, etc.) and used to transfer ions and saltsfrom the stem cells to blood of a patient via a stem cell organ device.The stem cell organ device may include a plurality of stem cell channelsand a plurality of fluid channels, where the plurality of stem cellchannels are separated from the plurality of fluid channels via amembrane. The stem cells are loaded into the stem cell channels of thestem cell organ device and kept alive via nutrient rich media. While thestem cells are loaded into the stem cell channels and before flowingblood through the device for patient treatment, media containingnutrients flow through the fluid channels of the stem cell organ device.The media is then flushed from the stem cell organ device with aflushing solution, such as saline, such that upon flowing blood into thestem cell organ device the fluid channels do not contain any leftovermedia. The blood and the stem cells may then exchange a variety ofnutrients and molecules across the membrane separating the stem cellchannels from the fluid channels. The membrane inhibits the exchange ofstem cells into the fluid channels and blood into the stem cellchannels. Blood is continuously flowed through the fluid channels whilethe stem cells are only flowed into the stem cell channels once beforepatient treatment

The technical effect of loading a stem cell organ device with stem cellsis to allow a patient in need of an organ transplant to receive medicaltreatment via stem cells mimicking the sought after organ. The stemcells are loaded into the stem cell device and used to exchangenutrients from the stem cells to the patient's blood while alsotransferring toxins and other unwanted components from the patient'sblood to the stem cells.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising,”“including,” or “having” an element or a plurality of elements having aparticular property may include additional such elements not having thatproperty. The terms “including” and “in which” are used as theplain-language equivalents of the respective terms “comprising” and“wherein.” Moreover, the terms “first,” “second,” and “third,” etc. areused merely as labels, and are not intended to impose numericalrequirements or a particular positional order on their objects.

This written description uses examples to disclose the invention,including the best mode, and also to enable a person of ordinary skillin the relevant art to practice the invention, including making andusing any devices or systems and performing any incorporated methods.The patentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

1. A method for a stem cell organ device fluidly coupled to a usercomprising: entering a blood bypass mode in response to stem cells beingless than fully loaded into the stem cell organ device, the blood bypassmode comprising flowing blood through a multi-fluid manifold and back tothe user without filtering the blood.
 2. The method of claim 1, whereinthe blood bypass mode further comprises flowing blood through a firstport of the multi-fluid manifold via a variable pump, wherein flowingblood through the first port comprises flowing blood through a bypasspassage fluidly coupling the stem cell organ device to the user, thebypass passage being fluidly separated from a plurality of fluidchannels in which the stem cells are arranged.
 3. The method of claim 2,further comprising entering a blood mode in response to stem cells beingfully loaded into the stem cell organ device, wherein blood flowsthrough a second port of the multi-media manifold, through the pluralityof fluid channels, and back to the user without entering the bypasspassage.
 4. The method of claim 3, further comprising filtering blood inthe blood mode, wherein each of the plurality of fluid channelscomprises a membrane, and where the membrane separates the stem cells ina fluid channel from blood so that stems cells and blood do not directlycontact one another, and where the membrane is shaped to allow nutrientsto pass from the stem cells to the blood and for salt, water, and toxinsto pass from the blood to the stem cells.
 5. The method of claim 2,further comprising exiting the blood mode in response to one or more ofstem cells being degraded and a threshold color change.
 6. The method ofclaim 5, wherein the stem cells are degraded in response to a saltconcentration being greater than a threshold salt concentration, a waterconcentration being greater than a threshold water concentration, and atoxin concentration being greater than a threshold toxin concentration.7. The method of claim 5, wherein the threshold color change isdetermined via one or more of an optical sensor arranged in the stemcell device and the user visualizing a color of the stem cells through atransparent glass cover layer of the stem cell organ device.
 8. Themethod of claim 2, further comprising entering a flush mode in responseto the stem cells being fully loaded, the flush mode comprising flowinga flush solution to and through the plurality of fluid channels, whereinflowing the flush solution further comprises the variable pump directingthe flush solution through a third port of the multi-fluid manifold, andwhere the flush solution and blood do not mix during the flush and bloodbypass modes.
 9. A method comprising: loading stem cells into aplurality of fluid channels during a media mode; flushing the pluralityof fluid channels with a flushing solution during a flush mode; andfiltering blood flowing on a side of a membrane in a fluid channel ofthe plurality of fluid channels opposite the stem cells during a bloodmode.
 10. The method of claim 9, wherein the flush mode furthercomprises removing media from the plurality of fluid channels, and wherethe flushing solution is saline.
 11. The method of claim 9, furthercomprising passing one or more compounds including water, toxins, salt,and nutrients through the membrane during the blood mode withoutallowing stem cells or blood to flow through the membrane.
 12. Themethod of claim 9, further comprising entering a bypass mode whichcomprises bypassing blood through a bypass passage during the media modeand the flush mode, wherein blood does not enter the plurality of fluidchannels during the bypass mode.
 13. The method of claim 12, wherein thebypass mode is terminated in response to the plurality of fluid channelsbeing fully loaded with stem cells and flushed with the flushingsolution.
 14. A system comprising: a stem cell organ device comprising aplurality of fluid channels, wherein a fluid channel of the plurality offluid channels comprises a membrane dividing the fluid channel into afirst fluid channel and a second fluid channel; a multi-fluid manifoldcomprising a plurality of ports for directing fluids to the first fluidchannel, the second fluid channel, and to a bypass passage; a variablepump configured to flow a plurality of fluids to the plurality of ports;and a controller comprising instructions stored in non-transitory memorythat when executed enable the controller to: enter a bypass mode inresponse to one of a media mode or a flush mode being executed; enter ablood mode in response to each of the media mode and the flush modebeing complete.
 15. The system of claim 14, wherein the variable pumpdirects blood through a first port of the multi-fluid manifold duringthe bypass mode, the first port being fluidly coupled to a bypasspassage fluidly separated from the plurality of fluid channels, andwhere the variable pump directs blood through a second port of themulti-fluid manifold during the blood mode, wherein the second port isfluidly coupled to the second fluid channel of the plurality of fluidchannels.
 16. The system of claim 14, wherein the variable pump directsmedia through a third port of the multi-fluid manifold to the firstfluid channel during the media mode, and where the variable pump directsa flushing solution through a fourth port of the multi-fluid manifold tothe first and second fluid channels during the flush mode, and where theflush mode is executed following the media mode.
 17. The system of claim14, wherein the flush mode is entered following completion of the bloodmode, wherein the blood mode is complete in response to a biomarkerindicating blood purity is greater than a threshold purity, wherein thebiomarker is one or more of a blood toxin, salt, and water.
 18. Thesystem of claim 17, wherein following completion of the flush modefollowing completion of the blood mode, the media mode is entered,wherein media flows to the first fluid channel to maintain a viabilityof stem cells arranged therein for a future treatment session.
 19. Thesystem of claim 14, wherein the stem cell organ device is a portabledevice, and where a patient receiving treatment from the device may walkor perform other activities while receiving a treatment from the stemcell organ device.
 20. The system of claim 14, wherein the bypass modecomprises blood returning to a patient without being filtered, and wherethe first fluid channel is a stem cell channel and the second fluidchannel is a blood channel.